A string of car bombings and shootings across Iraq left more than 50 people dead Monday, authorities said, in what is the latest spate of violence in a country plagued with Sunni-Shiite tension.

Scores were wounded in cities that were regularly engulfed in violence during last decade's Iraq war. The violence in recent weeks has conjured fears that all-out sectarian violence is rearing its head again in Iraq.

"Those who are targeting mosques and other locations are the enemies of Sunnis and Shiite," Prime Minister Nuri al-Maliki said this weekend. "They are plotting to ignite sectarian strife as they have tried before."

The ever-present tensions between Iraq's Sunnis and Shiites have escalated, especially after an incident last month in Hawija, in northern Iraq, where Iraqi security forces raided a site used by Sunni protesters to demonstrate against the Shiite-led government.

Most of the attacks Monday took place in the capital, Baghdad, where eight car bombs and a roadside bomb rocked predominately Shiite neighborhoods, police said. In all, at least 18 people were killed and more than 100 wounded the strikes, police and health officials said.

Near Samarra, at least 14 people were killed and eight wounded when a car bomb exploded on a bus carrying Iranian Shiite pilgrims Monday, police said. That strike, on a highway near the northern Iraqi city, raised fears because of Samarra's symbolism. Shiites regularly travel to the Askariya Mosque in Samarra. The bombing of the Shiite shrine in 2006 stoked the sectarian warfare.

In the southeastern city of Basra, in the Shiite heartland, at least nine people were killed and 37 wounded when two car bombs exploded Monday in a pair of neighborhoods. Most of the casualties were civilians, police said. It was unclear who was responsible for the blasts.

Gunmen ambushed two police checkpoints in Haditha on Monday, killing eight officers, Ramadi police said. Haditha is in the predominantly Sunni Anbar province, west of Baghdad.

In Hilla, south of Baghdad in Babel province, at least nine people were killed and 53 others were wounded when a suicide bomber and a roadside bomb exploded outside Shiite mosques Monday evening.

Over the weekend in Ramadi, the bodies of eight civilians who were kidnapped by gunmen Saturday were found, officials said. The civilians were abducted on a highway west of Ramadi, and their bodies were discovered late Sunday night along a different part of roadway, authorities said. All eight had been shot to death.

Earlier, the bodies of six police officers who had also been abducted Saturday were found on a highway in western Ramadi.